1. Field of the Invention
This invention relates to a cannula retractable medical collection device, more particularly to a cannula retractable medical collection device adapted to be used with a collection vial for collecting a blood sample therein, and having a cannula which is retractable into a barrel for safe disposal.
2. Description of the Related Art
Referring to FIGS. 1 and 2, U.S. Pat. No. 5,810,775 discloses a cap operated retractable medical device 1, which includes an outer body 11 with a hingedly connected outer cap 16 that is movable between open and closed positions. A movable member 12 is entirely mounted within the outer body 11. A retracting body 13 is held in a front end 121 of the movable member 12 by means of friction interference therebetween such that the front end 121 is frictionally fitted with the outer body 11 adjacent to a stop 112 formed on the outer body 11. A double-ended needle cannula 14 is installed in the retracting body 13. A biasing spring 15 is compressed between the retracting body 13 and the stop 112.
In use, a front needle end 142 of the needle cannula 14 is inserted into a patient's vein. A conventional rubber stopper collection vial (not shown) is inserted into the outer body 11 from an open back 111 thereof, and is pushed forward such that a rear needle end 141 of the needle cannula 14 punctures the rubber stopper and passes through a rubber sheath 17 for collecting a blood sample in the collection vial. The collection vial is then removed from the device 1 while the sheath 17 can restrict further flow of the blood. Thereafter, the cap 16 is operated to the closed position to engage an open back end 122 of the movable member 12 so as to move the movable member 12 forward, thereby triggering retraction of the retracting body 13 and the needle cannula 14.
Although the needle canula 14 can be retracted after use, the following drawbacks arise:
1. Since the collection vial has an outer diameter smaller than that of the movable member 12, a clearance exists therebetween so that the collection vial tends to shake during use, thereby resulting in pain to the patient.
2. Before retraction of the needle cannula 14, such as during transportation, before and during blood collection, the cap 16 has to be kept in the open position to prevent undesired retraction of the needle cannula 14, thereby resulting in inconvenient storage and transportation of the device 1.
3. The blood in the needle cannula 14 is not visible, thereby causing inconvenience to the user.
Furthermore, intravenous catheter inserting devices are generally used to administer medication fluid into or to draw blood from a patient's vein. Referring to FIG. 3, a conventional intravenous catheter inserting device 9 is shown to include a tubular needle seat 91 with a hub end 911, a needle cannula 92 secured to the hub end 911, a catheter hub 93 sleeved on the needle seat 91, and a flexible tubular catheter 94 secured to the catheter hub 93. In use, the catheter 94 and the needle cannula 92 are inserted into the patient's vein by a health care worker by piercing the patient's vein with a sharp tip of the needle cannula 92 which projects outwardly of the catheter 94. The health care worker then withdraws the needle cannula 92 from the catheter 94 with one hand and, at the same time, applies pressure to the patient's skin with the other hand, thereby leaving the catheter 94 in the patient's vein. Subsequently, a transfusion member (not shown) with medication fluid or an empty barrel is connected to the catheter hub 93 for administering the medication fluid into the patient's vein or for drawing blood. At this time, as the health care worker must place the used needle cannula 92 and the needle seat 91 on a tray (not shown) nearby, the exposed sharp tip of the used needle cannula 92 may create a danger of an accidental needle stick. Moreover, blood contamination may occur during connection of the catheter hub 93 to the transfusion member or the empty barrel.